Automatic speed-control device



May 22, 1923. 1,456,269

v c. c. FARMER AUTOMATIC SPEED CONTROL DEVICE FiledLJune 15, 1921 INVENTOR CLYDE CFARMER ATTORNEY Patented May 22, 1923.

UNETED STATES ATENT @FFEQE.

CLYDE C. FARMER, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE WESTING- HOUSE AIR BRAKE COMPANY, OF WILMERDING, ?ENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

AUTOMATIC SPEED-CONTROL DEVICE.

Application filed June 15, 1921. Serial No. 477,847.

To all whom it may concern Be it-known that I, CLYDE C. FARMER, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented new and useful Improvements in Automatic Speed-Control Devices, of which the following is a specification.

This invention relates to apparatus for controlling the speed of a train in accordance with the traffic conditions.

An equipment of the above character is disclosed in Patent No. 1,316,205 of Walter V. Turner, dated September 16, 1919.

In the patent construction, if the governor device should fail to function, by reason of a broken governor shaft, for example, the speed governing apparatus would be inoperative to regulate the speed of the train.

In Patent No. 1,355,189 of Thomas H. Thomas, dated October 12, 1920, there is disclosed a means for limiting the speed of the train to a predetermined low degree in case of failure of the speed governor device.

The principal object of my invention is to provide improved means for accomplishing the same purpose.

In the accompanying drawing, the single figure is a diagrammatic view, with the principal parts sectioned, of a speed controlling apparatus with my invention applied thereto.

As shown in the drawing, the main speed governor device may comprise a casing 1 having journaled therein a rotatable sleeve 2 with a pinion 3 secured thereto and having a geared connection with a car or locomotive axle.

Pivotally mounted on the sleeve 2 are governor ball arms a and journaled within the sleeve 2 is a sleeve 5 having a disk flange 6 adapted to be engaged by the arms 4. Mounted in the sleeve 5 is a shaft 7 having a cross-head 8 for engaging a plurality of valves 8 and 9 so as to determine the speed limit of the train, as in Patent No. 1,316,205.

An application valve device is provided comprising a casing 11 having a piston chamber 12 connected by a pipe 13 to a valve chamber 14 in the speed governor casing 1 and containing a piston 15. Said piston operates a slide valve 16, contained in valve chamber 17 for venting fluid. under pressure from the train. brake pipe 1'8 to efieet an ap plication of the brakes. The valve chamber 17 is connected to a source of fluid under pressure, such as the main reservoir 19.

According to my invention, an auxiliary governor device is provided comprising a casing 20 having journaled therein a member 21 which is rotatably connected to a car or locomotive axle. Said member carries pivotally mounted ball governor arms 22 adapted to engage a disk flange 23 for operating a shaft 2 1, the axial movement of the shaft 24 being employed to operate a valve 25 contained in a valve chamber 26.

A valve 27, contained in valve chamber 14 of the main governor casing 1, is operatively connected to the crosshead 8 and controls communication from pipe 13 and valve chamber 14;, through pipe and passage 28 to valve chamber 26.

In operation, fluid under pressure supplied to valve chamber 17 from the main reservoir 19 equalizes through the restricted port 29 in piston 15 to piston chamber 12, and the fluid pressures on opposite sides of the piston being equal, the spring 30 maintains the piston 15 and slide valve 16 in the normal position as shown in the drawing.

Under normal conditions, when the train is running at a speed above a predetermined low limit, the governor arms 1- operate to shift the cross-head 8, so that the valve 27 remains closed and the movement of the cross-head, according to the speed. of the train, operates the valves 9 and 10 to determine the speed of the train, as in Patent No. 1516205, herein referred to. If, however, the main speed governor should become inoperative for any reason, then the governor arms 4; would not rotate and the parts of the main governor device would be in positions shown, with the valve 27 held off its seat by the cross-head 8.

Communication is then established from the piston chamber 12 of the application valve device 11 through pipe 13 and valve chamber 14 to passage 28 and valve chamber 26 of the auxiliary speed governor device 20. The auxiliary governor device is so adjusted that if the speed of the train exceeds a predetermined low limit, the shaft 24 will be operated so as to lift the valve 25 from its seat and permit fluid to be vented from pipe 28 to an atmospheric exhaust port 31.

Fluid under pressure will then be vented from the piston-chamber 12 of the applica tion alve device at a greater rate than it can equalize through the restricted port 29, so that the piston 15 will be actuated by the higher fluid pressure in valve chamber 17 to shift the slide valve 16 to a position in which the brake pipe 18 is connected by a cavity 32 with an exhaust port 33.

The reduction in brake pipe pressure so produced causes an application of the brakes in the usual manner and the speed of the train is reduced until the speed is 10W enough to permit the retraction of the shaft 24 by the operation of the governor arms 22 and thereby the closing of valve 25. When the valve 25 closes. the venting of fluid from piston chamber 12 ceases and the fluid pressures again equalizing through port 29 on opposite sides of the piston 15, the piston returns to normal position so as to cut off the venting of fluid from the brake pipe 18, and the brake pipe being recharged With fluid under pressure, the brakes are released.

Having now described my invention, What I claim as new and desire to secure by Letters Patent, is

1. In a train speed control apparatus, the combination with a main speed governor device for determining the speed limit of the train, of an application valve device operated by a variation in fluid pressure for effecting an application of the brakes and an auxiliary speed governor device having a valve opertive at a predetermined train speed for varying the fluid pressure on said application valve device.

2. In a train speed control apparatus, the combination With a main speed governor device for determining the speed limit of the upon a reduction in fluid pressure for eta lecting an application of the brakes, an auxiliary speed governor device having a valve for venting fluid from said application valve device at a predetermined train speed, and a valve operated upon failure of the main speed control governor for opening communication from the application valve device to the auxiliary speed governor valve.

4. In a train speed control apparatus, the

combination with a main speed governor device for determining the speed limit of the train, of a valve device operated by variations in fluid pressure for limiting the speed of the train, and an auxiliary speed governvor for varying the fluid pressure on said valve device, and means operated by the main governor for controlling communication from said valve device to the auxiliary governor. 1

In testimony whereof I have hereunto set my hand. i

CLYDE C. FARMER. 

